Centerless grinder



March 1932- s. A. STRICKLAND ET AL CENTERLE'SS GRINDER Filed Nov. 26, 1928 4 Sheets-Sheet 1.

Illlll March 1932- s. A, STRICKLAND ET AL 1,850,054

CENTERLESS GRINDER Filed Nov. 26, 1928 4 Sheets-Sheet 2 INVENTOR March 1932- s. A. STRICKLAND ET AL 1,850,054

, CENTERLESS GRINDER Filed Nov. 26, 1928 4 Sheets-Sheet 5 e n W!!! Ix t swsfl 57%??? awe/7 ATTO RN EYS March 1932- I s. A. STRICKLAND ET AL 1,850,054

CENTERLES S GRINDER Filed Nov. 26, 1928 4 Sheets-Sheet 4 ATTORNE s Patented Mar. 15, 1932.

UNITED STATES PATENT OFFICE SILAS A. STBICKLAND AND THOMAS ZIMMERMLAN, DETROIT, MlICfHIG-AN, ASSIGNOBS,

BY iMESNE ASSIGNMENTS, T0 CINCINNATI GRINDERS INCORPORATED, OF O'INOIN- N ATI, OHIO, A CORPORATION OF OHIO CENTERLESS GRINDER Application filed November 26, 1928. Serial No. 321,807.

This invention relates to grinding machines of that class known as centerless grinders wherein the work is unrestrained by being held between positive fixed centers about which it rotates, but is positioned by means of a suitable support between a grinding wheel and a member which regulates the speed of rotation of the work and its contact with the grinding wheel.

Two methods of operation have heretofore been used in centerless grinding, one known as the through feed method and the other, the in-feed method. The through feed method is adapted for straight cylindrical pieces, said pieces being moved axially along a work rest between a grinding wheel and regulating wheel by a relative angular relationship of the work rest and the operative path of movement of a point of one of the wheels at the throat, which produces a feeding movement of the work along the work rest. The infeed method which has been commonly employed in the grinding of tapered or formed work, consists in supporting the work within the throat between grinding and regulating wheels without permitting travel along the support and subsequently withdrawing the work either by separation of the wheels or lateral displacement of the work. In the through feed method, it is very difficult, if not impossible, to grind the work and produce a perfectly true surface, particularly when employed on tapered work, due largely to the fact that the work is fed in a direction transversely to the plane of rotation of the grinding wheel, or, in other words, is fed across the face of the grinding wheel during the grinding operation, and in the in-feed method, the process is slow due to the constant adjustment of the grinding and regulating wheels in releasing the work and due to the time required for ejecting each piece.

Either method is not adapted to the grind- 1 ing of tapered rollers with the accuracynecessary to produce a perfect taper and with the facility required in the manufacture of such rollers.

Further, the prior methods commonly employed necessitate the frequent redressing of the grinding wheel and also of the regulatdown the abrasivesurface of the regulating member, thus requiring frequent trru'ng of this face. Such truing is particularly necessary where the in-feed method is employed for grinding a particular form or configuration of work. h

It is an object of the present invention to overcome the several disadvantages of the prior methods above pointed out, and other. difficulties and disadvantages of such prior methods, this present method being distinguished from both in-feeding and through feeding methods in that in the present method the workis fed in between the grinding and regulating members and is released therefrom and discharged from the machine without the necessity for feeding the work across the face of the grinding wheel or moving the' grinding wheel and regulating member relatively to effect such release.

A further object is to provide an arrangement whereby the work is held against movement across the face of the grinding wheel or across the face of the regulating member and is caused by its engagement with said wheel and member, to rotate in a fixed plane during a single rotation of the regulating member, said regulating member being so formed as to permit the free insertion of the work within the throat between the grinding wheel and member at the beginning of each rotation of the member, to thereafter bring the work into contact with the grindin wheel, and to release and discharge the wor adjacent the end of each rotation of the member.

A further object is to provide suitable means for supporting the work within the throat during the grinding operation, in such a manner as to produce a true surface, which means is so arranged as to provide for free lateral release of the work at the end of the grinding operation.v It is also an object to simplify the construction and secure a maxforth in the appended claims, reference had to the accompanying drawings in which Y Figure l'is a side elevation of a portion of a machine illustrative of an embodiment of the present invention, with portions broken away and in section to more clearly disclose the construction;

Fig. 2 is a horizontal section substantially upon the line 22 of Fig. 1;

Fig. 3 is a sectional detail showing the I mechanism for feeding in the work, said mechanism being shown in longitudinal section, and showing a rotary regulating member in side elevation, said section being taken substantially upon the line 33 of Fig. 1, and looking toward the regulating member;

Fig. 4 is a side elevation of a regulating member detached;

Fig. 5 is a vertical section through the machine showing feed mechanism and roller supporting means in elevation, looking in a direction opposite to that of Fig. 3, and with the regulating member removed;

Fig. 6 is a sectional detail illustrative of the position of a work piece at the point of its introduction into the throat between grinding wheel and regulating member;

Fig. 7 is a sectional detail similar to that of Fig. 6 illustrative of the position of a tapered roller between grinding wheel and regulating member during the grinding operation; and

Fig. 8 is a view similar to Fig. 7, and showing a slightly modified construction.

Referring to the drawings, 1 indicates a portion of a suitable base or supporting frame, 2 an arbor supported in a suitable bearing 3 and upon which arbor a grmdlng wheel 4 is secured with its periphery in proper spaced relation to the periphery of a regulating wheel 5 mounted in any suitable manner upon an arbor 6 which 18 rlgidly mounted in a bearing 7 the longitudinal axes of the bearings 3 and 7 being in a common horizontalplane and so spaced as to provide a narrow space or throat between the per1pheral faces of said wheels, said bearings belng a part of or mounted upon the frame in any desired manner, not shown, for r1g1dly and unyieldingly and, if deslred, adjustably supporting the arbors 2 and 6 and permitting free rotation thereof and the wheels 4 and '5 carried thereby. These wheels are rotated in the same direction and at the desired peripheral speeds by any suitable means, not shown, the peripheral speedof one wheel being different from that of the other so that of the plane of'rotation of said wheels, said means being the subject matter of a separate application for patent, filed December 6, 1928, Serial No. 328,328, but including generally a' tube 9 forming a chute for the rolls and which chute is properly fixed in an inclined position to discharge the rolls, one at a time, onto a reciprocable slide 10 supported in a suitable way 11 provided therefor upon an upward extension of or bracket 12 on the frame 1. This slide is reciprocated in timed relation to the rotation of the wheel 5 by means of a roller 13 connected to the slide and adapted to travel over a cam surface 14 on the end face of the wheel. The slide is urged toward the Wheel and said roller 13 is held in engagement with its cam by means of a spring let and the upper side of the slide 10 is stepped and tapered to engage beneath the rolls fed thereto and feed, at each reciprocation of the slide, a roll into the throat between the wheels. A spring pressed foot 15 is arranged to engage the forward roll in the series of rolls resting upon the slide 10 and hold the series against forward movement until such time as the slide is again operated to eject a roll into the grinding throat.

As the grinding wheel 4, and regulating wheel 5 are normally held at a fixed peripheral distance apart and as this distance must be less than the diameter of the roll being a ground in order to produce a grinding action,

a sector of the circumference of the regulatingb wheel is so formed as to permit a roll to feed in Fig. 4, is opposite the feed slide 10, and the cam portion 14 of the wheel 5 is a so located relative to this feed sector of the wheel that the slide will be operated in proper timed relation to the rotationof said wheel to feed in a roll 8 while this sector of the wheel is oppositethe slide.

To prevent endwise movement of the roll after 1t has been inserted in the throat and its endwise escape therefrom, the regulating wheel 5 is formed with a peripheral groove which provides an outstanding rib 16 to engage the large end of the roll and prevent its endwise movement away from the side of the groove through which it was inserted, and as the roll 8 is a tapered roll, the bottom wall 17 of said groove is inclined transversely of the wheel, the angle of this incline being twice the angle of the taper of the roll surface so that when the roll is in grinding position roll would not between the peripheral surface of the grinding wheel and the bottom surface 17 of said groove, the surface of said roll in contact with the right angle peripheral surface of the grinding wheel will contact said grinding surface throughout the length of the roll. In other words, the roll will be tilted within the throat so that the surface of the roll in contact with the peripheral surface of the grinding wheel will conform thereto, said grinding surface being exactly parallel with the axis of rotation of the grinding wheel. If found desirable, however, the grinding surface of the grinding wheel may be formed at an angle corresponding to the angle of taper of the roll as illustrated in Fig. 8, and the bottom wall 17 of the groove also formed at a corresponding angle, and in that case the be tilted when engaged between said surfaces.

When a roll 8 is in position within the throat formed between the inding and regulating wheels, it is held against endwise movement by engagement with the rib 16 and inclined bottom wall 17 of the groove 1n the wheel 5, it being held in said groove by its engagement at its opposite side with the grindin wheel, but it is necessary to support this rol against skewing or endwise tilting, that is with the horizontal plane of the roll axis parallel with a like plane passing through the axes of the grinding and regulating wheels, for if permitted to skew or tilt endwise, the roll will not contact the face of the grinding wheel along a line normal to said face and the roll will be ground with a concave or hour-glass formation instead of a true cylinder or cone.

To so support the rolls within the throat, a pair of plates 18 and 19 is secured to a suitable supporting bracket 20 on the base frame 1, with the adjacent edges of said plates spaced a art slightly and with an end portion of t e plates projecting into the throat or space between said grinding and regulating wheels. This end portion of each plate is cut away at one side or concaved as at 21 to conform to the curvature of the periphery of the wheel 5 and permit the entrance of this end portion between the wheels, and at the extreme end of each plate, the adjacent edges of the plates are beveled as at 22, to co operate in forming a notch or seat to receive and sup rt the rolls 8, said notch being tapered m the direction of its length to conform to the taper of the roll 8 and thus support the roll, when forced laterally into this notch by the engagement of the regulating wheel with the opposite side of the roll, with the line of contact of the grinding wheel with the roll, lying in the longitudinal axial plane of the roll, that is, with the roll extending straight across the face of the wheel in contact therewith throughout its length. The

roll will therefore be ground with a true taper as distinguished from a slight concave which would result from supporting the roll in a slightly tilted or angular position relative to the wheel face.

In order to adjust the lates 18 and 19 so that the notch formed by t e beveled edges 22, to receive the work may be in the proper position to properly hold the work, the bracket 20 which carries these plates, is pivoted at 23 on the base frame 1 and bolts 24 passing throu h curved slots 25 in the bracket are provided to lock the bracket in adjusted position. The bracket may thus be swung laterally about the pivot 23 which is directly below the work supporting end of these plates and change the longitudinal direction of the work receiving notch relative to the peripheral grinding face of the grinding wheel. Bolts 26 secure the plate 19 against the vertical face of the bracket 20 and set screws 27 passing through lugs 28 on the base frame, engage the late 18 and secure it firmly against the brac et in proper relation to the plate 19. A set screw 29 passing through a bracket 30 on the base frame 1, engages one side of the bracket 20 to assist in accurate adjustment thereof about its pivot 23.

In order to provide for the free entrance of the work pieces into the notch in the supporting (plates within the throat between the grin ing and regulating wheels, a portion of the peripheral groove in the regulating wheel is formed to a greater depth, as at 31, extending from an edge notch 32- in the wheel through a small portion or sector of the circumference of the wheel indicated by the word feed in Fig. 4, and gradually tapering outwardly until it merges into a larger diameter extending through a larger portion or sector 32 indicated in Fig. 4 by the word rinding. This portion 32 may be formed slightly eccentric to the wheel axis, gradually mer ing into the concentric or what is indicate at 33 as the finishing portion of the groove which ends in the notch 32 or that portion designated in Fig. 4 as the ejector. The diameter of the regulating wheel as defined by the bottom wall 17 of its peripheral groove is thus reduced sufficiently throughout the sector 31 so that the rolls 8 may be inserted endwise by the operation of the slide 10 into the notch of the supporting plates 1819 and between the peripheries of the grinding and regulating wheels. After such insertion which is in timed relation to the rotation of the regulating wheel due to the location of the cam notch 14 opposite the sector 31, further turning of said wheel will gradually force the work radially outward toward the grinding wheel and into abrading contact therewith, which'abrading action will continue throughout the sector 32 until the roll has been reduced to the desired diameter at the end of said sector. From that point on to the notch 32 the roll will be finish ground, as this portion of the groove is concentric .with the axis of the wheel. When the notch 32 comes opposite the work, the work will be released and drop by gravity out of the machine, the bottom of said notch being inclined in a direction laterally of the wheel 5 as indicated at 34.- in Fig. 3 and the rib 16 and groove being cut away by said notch, releasing the work which has been confined in said groove and held in its supporting notch in the supporting plates throughout the rotation of the wheel until said ejecting or discharge notch 32 comes opposite the work.

The tapered or truncated conical work pieces are thus fed, one at a time and in timed relation to the rotation of the regulating wheel, into the throat regulating wheels, are rotated upon their own axes in contact with the supporting plates by the differential rotation of said wheels to produce the desired abrading action, the speed of rotation of said wheels being such as to produce the desired grinding action, they are then subjected to a period of finishing or burnishing and finally discharged, one at each rotation of the regulating Wheel, through the notch 32 and into a suitable chute (not shown) which may be conveniently supported by a hanger 35 attached to one of the bolts 26.

As shown in Fig. 1 of the drawings, the work piece or roll 8 is preferably supported in its seat between the beveled ends 22 of the plates 18 and 19, slightly above the horizontal plane of the axes of the grinding and regulating wheels so that the downward movement of the periphery of the grinding wheel in the direction of the arrow in Fig. 1 will tend to move said work further into the narrowest portion of the throat and grip the work between grinding and regulating wheels without forcing it into undue frictional contact with the lower side or bevel 22 of the notch in which it is supported, the upward motion of the periphery of the regulating wheel in the direction of the arrow in. said Fig. 1, tending to counteract such wedging of the piecebetween the grinding wheel and the bottom 17 ofthe'single continuous peripheral groove in the regulating wheel.

With this arrangement work having a tapered or conical formation may be very accurately ground to a perfectly true cone, and the work may be fed in and discharged auto matically, without the necessity for separating the grinding and regulating wheels to eject the work with consequent inaccuracies in the finished product or without the necessity for feeding the work pieces transversely of the face of the grinding wheel. Further, if found desirable, it permits of moving the grinding wheel in the direction of its axis of rotation so that there will be even wearing away of the face across its entire width, but provision for such movement of the grinding between grinding and wheel is not shown in the accompanying drawings as it is an old and well known expedient in the grinding art.

Obviously changes may be made in wheel diameters and in their relative diameters, also in the form, construction and arrangement of the regulating wheel within the scope of the appended claims, and duplication of parts and other means employed in carrying out the invention, as well as the substitution of mechanical equivalents therefor are contemplated.

Having thus fully what we claim is 1. In a machine of the character described, the combination of a grinding wheel, a rotative regulating member in oppose-d relation to the grinding wheel and forming a throat therebetween, the axes of the wheel and member having a fixed distance relation in service, and a work support in said throat, said regulating member being formed with a peripheral work receiving groove disposed throughout its length in single transverse plane of the member, said groove having a portion thereof formed to provide for the insertion therein of work and a portion formed to permit of the discharge of work therefrom.

2. In a machine of the character described, the combination of a grinding wheel,,a regulating wheel in opposed relation to the grinding wheel and forming a throat therebetween, and a work support within said throat, said regulating wheel being formed with a path operative to engage work on said support and prevent movement thereof across the abrading surface of the grinding wheel, said regulating wheel being also formed with a portion to permit the insertion of work into said throat upon said support and a portion to provide for the discharge of the work.

In a machine of the character described, the combination of a grinding wheel, a regulating wheel in opposed relation to the grind.- ing wheel, and a work support between said wheels, said work support being formed to support the work against shift in work axis relation to the path of movement of the a-brading surface of the grinding wheel and permit rotation of the work in contact with said surface, said regulating wheel being arranged to hold the work seated in its seat on said support and to limit endwise movement of the work.

4. In a machine as characterized in claim 3 and further characterized in that said regulating wheel is formed with a path for the work with a portion of said path formed to permit insertion of work between said wheels upon said support and a part formed to permit work to leave the support and be released from between said wheels.

5. A machine for grinding conical bodies including a grinding wheel, a regulating wheel in opposed relation to said grinding described our invention,

above and below t wheel and forming a throat between said wheels, and a wor support in said throat formed to receive and hold a conical body in contact with said grinding wheel with the line of contact between the cone surface and wheel extending parallel with the axis of rotation of said wheel, said regulating wheel being formed with a peripheral path cooperating with said work support in positioning and holding the conical bodies against endwise movement in such work axis during the grindin operation.

6. A mac ine as characterized in claim 5 and wherein said work support extends above and below the throat and is formed with a notch to receive the conical body with said notch formed to conform with the shape of said body and permit one side of said body to pro ect through said notch into contact with said grinding wheel.

7. In a centerless grinding machine, the combination of a rotatable grinding wheel, a rotatable regulating wheel arranged with its periphery in opposed spaced relation to the peripher of said grinding wheel, said reguating w eel being formed with a peri heral groove to receive work pieces and wit portions of said groove formed eccentric to the axis of rotation of said wheel, a peripheral portion of said regulating member being cut away to permit the escape laterally of said wheel of said work pieces, and a support for work pieces positioned betwen said grinding and regulatingl wheels and extending e position of the wor pieces while being ground.

8. A machine as characterized in claim 7 and wherein said work support is formed with an openin to receive and hold work pieces,and inc uding means for inserting work ieces into said .opening.

9. X centerless grinder including a grinding wheel, a rotatable regulating member with its periphery in opposed and spaced relation to the periphery of said grinding wheel, said regulating member being formed with a peripheral groove to receive a work piece with a portion of said groove of a.

greater depth than the remaining portion to rmit the endwise insertion of a work piece into the groove through the space between said grinding and regulating members, said oove terminating in a peripheral notch in said regulating member to release said work piece from the groove, and a support for the work projecting into the space between said grinding and regulating members and formed with an opening at the end of said support to receive and hold the work piece during the grinding operation.

10. A centerless grinder as characterized in claim 9 and further characterized in that said opening in said work support opens through one end of the support to permit the insertion of a work piece therein with one side of the work projecting through the opening into contact with the grinding wheel the opposite side of the work being engaged by the regulating member to hold the work in said opening and said opening being riphery of the grinding wheel, said regulating wheel being formedfwith a peripheral groove lying in a single transverse plane of the regulating wheel and providing an outstanding rib at one side of said groove forming an end abutment for said bodies, the bottom of said groove being inclined transversely of said wheel to correspond with the included angle of the conical body received in said groove and portions of said bottom formed eccentric to the axis of rotation of said regulating wheel, said regulating wheel having a peripheral opening at the termination of said groove to permit discharge of work from the, groove, a work support between said grinding and regulating wheels, and means operated by rotation of said regulating wheel and in timed relation thereto to feed conical bodies onto said support between said grinding and regulating wheels.

support, a grinding wheel mounted thereon and rotatable at a high grinding rate of speed, a regulating wheel mounted thereon in peripheral opposition to the grinding wheel and rotatable at a'slow work controlling rate of speed, and a work support disposed intermediate the wheels characterized by the fact that the regulating wheel has a substantially spiral peripheral surface whereby on rotation of the regulating wheel said surface will sequentially advance toward and recede from the opposed grinding wheel surface to vary the width of the work receiving throat therebetween.

13. A centerless grinding machine including a bed, a work support carried thereby, a grinding wheel disposed at one side of the support and rotatable at a high grinding rate of speed, and a regulating wheel disposed at the opposite side of the support in opposition to the grinding wheel for determining the relation of a work piece to the grinding wheel, said regulating wheel having a portion of the periphery thereof shaped in an advancing convolute for eflecting'a determined movement of the work toward the grinding of speed, and a regulating wheel disposed at the opposite side of the support in opposition to the grinding wheel for determining the relation of a work piece to the grinding wheel, said regulating wheel having a portion of the periphery thereof shaped in an advancing convolute for efi'ectin a determined movement of the work towar the grinding wheel on rotation of the regulating whee said regulating wheel having an additional portion of its surface formed substantially concentric with its axis of rotation for main tenance of an advanced work piece in definite relation to the grinding wheel.

15. A centerless grinding machine including a bed, a work support carried thereby, a grinding wheel disposed at one side of the support and rotatable at a high grinding rate of speed, and a regulating wheel disposed at the opposite side of the support in opposition to the grinding wheel for determining the relation of a work piece to the grinding wheel, said regulating wheel having a portion of the periphery thereof shaped in an advancing convolute for effecting a determined movement of'the work toward the grinding wheel on rotation of the regulating wheel, said regulating wheel having a projecting flange adjacent the convolute for lim iting endwise movement of the work within the throat.

16. A centerless grinding machine including a bed, a work support carried thereby, a grinding wheel disposed at one side of the support and rotatable at a high grinding rate of speed, and a regulating wheel disposed at the opposite side of the support in opposition to the grinding wheel for determining the relation of a work piece to the grinding wheel, said regulating wheel having a portion of the periphery thereof shaped in an advancing convolute for effecting a determined movement of the work toward the grinding wheel on rotation of the regulating wheel, said regulating wheel having a projecting flange adjacent the convolute for limiting endwise movement of the work within the throat and having a recess formed in the periphery thereof permitting lateral dis placement of the work piece in the throat.

17. A centerless grinding machine including a bed, a work support carried thereby, a grinding wheel disposed at one side of the support and rotatable at a high grinding rate of speed, and a regulating wheel disposed at the opposite side of the support in opposition to the grinding wheel for determining the relation of a work piece to the grinding wheel, said regulating wheel having a portion of the periphery thereof shaped in an advancing convolute for effecting a determined movement of the work toward the grinding wheel on rotation of the regulating wheel, said regulating wheel having a projecting flange adjacent the convolute for limplacement of the work piece in the throat,

and means adjacent the regulating wheel for .receiving a work piece discharged from the relieved portion.

18. A centerless grinder including a work support, a grinding wheel adjacent thereto and rotatable at a high grinding rate of speed for operation on a work piece carried by the support, and an opposed regulating wheel for controlling the position of a work piece on the support with respect to the grinding wheel, said regulating wheel having a non-cylindrical peripheral work engaging face including adjacent variably relieved portions whereby a work piece may recede from the grinding wheel for ejection at one of said portions and a new workpiece may be inserted in the temporarily widened throat provided by the adjacent relieved portions.

19. A centerless grinder including a work support, a grinding wheel adjacent thereto and rotatable at a high grinding rate of speed for operation on a work piece carried by the support, and an opposed regulating wheel for controlling the position of a work piece on the support with respect to the grinding wheel, said regulating wheel having a non-cylindrical peripheral work engaging face including adjacent variably relieved portions whereby a work piece may recede from the grinding wheel for ejection at one of said portions and a new work piece may be inserted in the temporarily widened throat provided by the adjacent relieved portions, said regulating wheel having the sur-. face thereof adjacent said relieved portions shaped to a progressively increasing convolute in a direction opposite the direction of rotation of the wheel whereby the grinding throat will be progressively narrowed during rotation of the regulating wheel.

20. A centerless grinder including a work support, a grinding wheel adjacent thereto and rotatable at a high grinding rate of speed for operation on a work piece carried by the support, and an opposed regulating wheel for controlling the position of a work piece on the support with respect to the grinding wheel, said regulating wheel having a noncylindrical peripheral work engaging face including ad acent variably relieved portions whereby a work piece may recede from the grinding wheel for ejection at one of said portions and a new work piece may be inserted in the temporarily widened throat provided by the adjacent relieved portions, said regulating wheel having the surface thereof adjacent said relieved portions shaped to a progressively increasing convolute in a direction opposite the direction of rotation of the wheel whereby the grinding throatwill be progressively narrowed during rotation of the regulating wheel, said regulating wheel having an additional substantially concentric portion of appreciable angular magnitude for maintaining a definite width of grinding throat during final grinding of the work piece.

21. A regulating wheel member for use in connection with a centerless grinder 'compris- 1 ing a disk rotatable about a determined axis having its periphery arcuately divided into a pluralityof blended portions including a variable advancing eccentric or spiral portion for sequentially effecting rapid and gradual restrictions of a grinding throat, and a concentric portion for subsequently maintaining the throat constant in size during an arcuate movement of the wheel of appreciable angular magnitude.

22. A regulatlng wheel member for'use in a connection with a centerless grinder comprising a disk rotatable about a determined axis having its periphery arcuately divided into a plurality of blended portions including a variable advancing eccentric or spiral portion for sequentially efiecting rapid and grad- I ual restrictions of a grinding throat, and a concentric portion for subsequently maintaining the throat constant in size during an arcuate movement of the wheel of appreciable angular magnitude, said'inember having spaced bounding flanges for terminal engagement.

restrictions of a grinding throat, and a concentric portion for subsequently maintaining the throat constant in size during an arcuate movement of the wheel of appreciable angular magnitude, said member having spaced bounding flanges for terminal engagement with a work piece to restrain its axlal movement in either direction, said disk having a relieved portion in its periphery for reception of a Work piece at the completiofl of the grinding operation. C

24. A regulating wheel member for use in connection with a centerless grinder comprising a disk rotatable about a determined axi having its periphery arcuately divided into a plurality of blended portions including a variable advancing eccentric or spiral portion for sequentially effecting rapid and grad-- ual restrictions of a grinding throat, anda concentric portion for subsequently maintaining the throat constant in size during an arcuate movement of the wheel of appreciable angular magnitude, said member having spaced bounding flanges for terminal engagement with a work piece to restrain its axial movement in either direction, one of said flanges having a relieved portion whereby a space is provided permitting axial introduction of a work iece into the space enclosed by the bounding anges.

In testimony whereof we afiix our signatures.

SILAS A. STRICKLAND. THOMAS ZIMMERMAN. 

